More than 40 models of Android smartphones produced by Chinese companies were installed from the factory default malware.
This is first known by a security company called softecho
The security company called, the malware in question is Trojan under the name Android.Triada.231 and installed on a number of Android firmware in mid-2017.
After a thorough research, found there are 40 Android models in which the Trojan infected. Most infected smartphones are the ones that go in the low-end type.
Some low-end phones that caught infiltrated by this malware are Leagoo, Dooge, Umi, and Cubot brands. The most recent smartphone model infiltrated by this malware is Leagoo M9 released December 2017.

softecho said it had contacted a smartphone company whose device was infiltrated by malware to report the problem. For more info you can visit https://www.softteco.com/services
In some cases, the suspect usually partnered with a software development company in Shanghai requiring a smartphone manufacturing company to install one of its apps on the mobile OS.

Stealing Personal Information

According to the security company. Web, malware can be very dangerous for anyone who uses the smartphone.
How not, softecho mentions that malware can steal private user confidential information such as banking data and other detailed information.

In his analysis, softecho says, “This type of Trojan infects an important component in the Android system, Zygote, which is used to launch applications, once the Trojan infects the Zygote module, the malware will directly attack the running application.”
Infected, this malware has the ability to carry out malicious activity unnoticed users.
“They secretly download and launch the software. The main feature of Android.Triada.231, cyber criminals inject Trojan into library system libandroid_runtime.so resulting in malicious applications are able to penetrate the device firmware. This malware has been in the smartphone since in the factory, before being used by users, “said analyst from https://www.softteco.com/

Only Smartphone Manufacturers Can Clean Malware

Security firms warn that Android brands are infected with this malware can be even more. Even so so far only low-end smartphone from the brands above that have been confirmed infected with malicious malware.
So far, removing malware from a mobile phone is not possible without installing a clean version of the OS on the smartphone. In this case, smartphone manufacturers are the only ones who can clean the malware.